1. Field of the Invention
This invention relates generally to seal assemblies, particularly to seal assemblies for rotating machinery, and more particularly to seal assemblies for pressurized rotary kilns.
2. Description of the Prior Art
The use of rotary kilns and the like has increased considerably over the past few years, particularly in the recovery of hydrocarbons by heating carbonaceous materials such as scrap rubber, coal, oil shale etc.. The efficiency of such rotary kilns can be substantially increased by their operation at a positive kiln chamber pressure.
While it has proved difficult to provide a satisfactory seal between the rotating surfaces and the stationary surfaces of the rotary kiln so as to maintain the positive internal pressure within the kiln, problems of seal fouling and leaking have also arisen as a result of hydrocarbon and particulate contamination caused by fluid communication between the kiln chamber and the sealing surfaces. It has also proven desirable to provide a seal assembly and method which is adjustable as to the tightness of the seal so as to provide the proper sealing depending on the particular pressure within the kiln chamber.
It is therefore the primary object of this invention to provide a rotary kiln having a new seal assembly, and to provide a method for providing an effective seal between the rotating surfaces and the stationary surfaces of the rotary kiln.
It is a further object of this invention to provide a means and method for sealing a pressurized rotary kiln so as to maintain the positive internal pressure of the kiln chamber.
It is an additional object to provide a sealing means and method which will prevent the fouling of the seals by contaminants produced in the kiln.
It is yet another object to provide a sealing means and method for providing an adjustable seal which can be adjusted to the internal kiln pressure.
These, and other objects to become apparent to those skilled in the art, are provided for by the invention which will be described hereinafter.